A tillage implement equipped with rows of spaced apart individually mounted coulter wheel assemblies is known in the art for use in conservation tillage. An example is provided in commonly owned U.S. Pat. No. 7,762,345, which is incorporated herein by reference.
Some coulter wheel assemblies are known to use springs having a horizontal spring axis, such as is shown in commonly owned U.S. Pat. No. 6,412,571, which is incorporated herein by reference.
An example of a tillage implement comprising spaced apart rows of individually mounted tillage blade assemblies having a concave disc blade and a shank with a spring having a horizontal spring axis is provided in commonly owned US patent application published as US 2011/0132628, which is incorporated herein by reference.
An example of a blade assembly and tillage implement equipped therewith comprising a resilient element in place of the coil spring is provided in commonly owned US patent application published as US 2011/0132627, which is incorporated herein by reference.
In conventional tillage operations using implements equipped with concave disc shaped tillage blades (for example, disc harrows), the soil is turned at the site of the disc and crop residue between the discs is buried by thrown soil. In such conventional tillage implements, the disc shaped blades are normally oriented with the concave side of adjacent discs facing the same direction. For example, referring to prior art FIG. 9, a disc harrow is equipped with a first set of concave disc shaped blades 300 mounted on a first common gang shaft 301 with the concave side of the blades facing towards the center of the implement, while a second set of concave disc shaped blades 310 is mounted on a second common gang shaft 311 with their concave sides facing away from the center of the implement. This causes soil to be transferred either towards the center of the implement, leaving a ridge, or away from the center, leaving a valley. In practice, a more acute angle between the gang shafts 301, 310 and the direction of travel of the implement leads to greater soil throw and greater coverage of crop residue between the disc shaped blades, but also leads to larger center ridges and larger valleys at the outside edges of the disc harrow. The farmer is therefore always forced to strike a compromise between effective crop residue coverage and the levelness of the soil surface following tillage.
There is a need for improved tillage implements and methods of use thereof that provide both effective crop residue coverage and a level soil surface following tillage.